"There are many reasons why a Heisman winner can’t repeat (outside of Archie Griffin, of course). For starters, imagine how hard it is for a player to have ONE Heisman-worthy season. But to have back-to-back Heisman-worthy seasons? Forget about it!

"Furthermore, once such a season is accomplished, it must also be perceived as more worthy than all the other candidates in the running. In essence, everything has to fall perfectly into place for a player to win the Heisman ... once. For things to fall perfectly into place twice is highly unlikely."

And Tebow's biggest competition could be himself.

"He will be running not only against his peers, but the legacy of his incredible 2007 performance. If his stats do not compare to his sophomore season, then it will be hard to avoid the perception that he underachieved."